BIOLOGICAL PROPERTIES OF RPE MELANIN

描述（由申请人提供）：拟议的长期目标 保护视网膜色素上皮（RPE）免受氧化应激。氧化 老年RPE的损伤可能会降低其支持视网膜的能力， 光感受器，导致老年性黄斑变性等疾病。 这种应用程序集中在黑色素。黑色素是一种 RPE细胞的特性，在某些条件下可以显示抗氧化特性， 虽然黑色素还没有被仔细研究以确定它是否 保护细胞免受氧化应激。RPE细胞的黑色素是 不寻常的是，它在胚胎发生后几乎没有周转， 因此，容易受到年龄变化的影响。的基本假设 这种应用是黑色素保护RPE细胞免受氧化应激 蓝光、氧化还原活性金属离子和反应性金属离子在视网膜外层诱导 氧物种，但老化改变黑色素的物理化学性质， 降低其作为抗氧化剂的效率。在这个项目中， 一位生物制药学家计划利用灵敏的电子自旋共振技术 (ESR)方法，细胞培养模型，以及几种生化和形态学 氧化应激和细胞毒性的措施，以解决这些具体目标： (1)为了确定牛或人RPE黑色素是否抑制脂质 过氧化作用，老化是否会影响这种性质，以及 黑色素的假定抗氧化功能可以通过实验来鉴定， 改性颜料颗粒。(2)完整地或实验性地引入 修饰的黑色素颗粒通过吞噬作用进入培养的人RPE细胞系 （ARPE-19细胞），以确定黑色素是否作为抗氧化剂的功能， 保护细胞免受光或化学诱导的氧化 应力(3)为了确定抗氧化和细胞保护特性 来自年轻人和老年人捐赠者的黑色素在氧化应激中的差异 细胞，以及RPE细胞是否老化，使用复制模型 衰老，调节黑色素的抗氧化功能。仔细的分析 黑色素的理化性质，再加上测试其生物 视网膜色素上皮细胞内的功能，将提供有关视网膜色素上皮细胞的基本信息。 重要的一类RPE颗粒，其性质可能随年龄而变化。

DESCRIPTION (provided by applicant): The long-term objective of the proposed protect the retinal pigment epithelium (RPE) from oxidative stress. Oxidative injury to the aged RPE may reduce its ability to support retinal photoreceptors, contributing to diseases like age-related macular degeneration. This application focuses on the pigment melanin. Melanin, which is a hallmark feature of RPE cells, can show antioxidant properties under some conditions, although melanin has not been carefully investigated to determine whether it actually protects cells from oxidative stress. The melanin of RPE cells is unusual in that it shows little turnover after embryogenesis and it may, therefore, be susceptible to changes with age. The underlying hypothesis of this application is that melanin protects RPE cells from oxidative stress induced in the outer retina by blue light, redox active metal ions and reactive oxygen species, but aging modifies melanin's physicochemical properties, reducing its efficiency as an antioxidant. In this project a cell biologist and a biophysicist plan to collaborate, using sensitive electron spin resonance (ESR) methods, cell culture models, and several biochemical and morphologic measures of oxidative stress and cytotoxicity, to address these specific aims: (1) To determine whether bovine or human RPE melanin inhibits lipid peroxidation, whether aging affects this property and whether the mechanism of melanin's putative antioxidant function can be identified by experimentally modifying the pigment granules. (2) To introduce intact or experimentally modified melanin granules by phagocytosis into a cultured human RPE cell line (ARPE-19 cells) to determine whether melanin functions as an antioxidant within cells and protects cells from photically- or chemically-induced oxidative stress. (3) To determine whether the antioxidant and cyto-protective properties of melanin from young and aged human donors differs in oxidatively-stressed cells, and whether cellular aging of the RPE, using the model of replicative senescence, modulates melanin's antioxidant function. Detailed analysis of the physicochemical properties of melanin, coupled with testing of its biological functions within RPE cells, will provide fundamental information about an important class of RPE granules whose properties may change with age.